Session qos control apparatus

ABSTRACT

A session QoS control arrangement wherein for an occurrence of user session information indicating a change of user state and/or a change of session condition from a user communication terminal: said session information analysis means analyses the session state of the user terminal in real-time by referring to said session management database and said user preference database; and, said session QoS control means determines the QoS policy for the user session in real-time, based on the result of session analysis performed by said session information analysis means.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation of U.S. application Ser. No. 10/985,944, filedNov. 12, 2004. This application relates to and claims priority fromJapanese Patent Application No. 200310114295.7, filed on Nov. 12, 2003.The entirety of the contents and subject matter of all of the above isincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates in general to a communication apparatususing a SIP protocol, and, more particularly, the invention relates to aQoS (Quality of Service) control method for routers on a network, basedon user preference information.

In peer-to-peer communication, in which a one-to-one connection isestablished between corresponding end users, a session between usercommunication terminals is established by a session control protocoltypified by the Session Initiation Protocol (SIP) specified in theRequest for Comments (RFC) 3261, a Recommendation for InternetStandards, and a communication of real-time data, such as audio andvideo, is performed in the session. In the use of SIP, a SIP server thatrelays session control messages locates a callee's terminal and effectsthe management of session information, such as terminal information andpeer-to-peer communication information. Besides, to satisfy calling andcalled user requirements, session control for the users is performed,based on a database, which is called a user preference.

On the other hand, network operators, such as communication carriers andInternet Service Providers (ISPs), rely on communication qualityassurance policies and routing control policies, which are generallycalled policies. The policies are managed by a policy server in anintegrated manner, and a great number of nodes constituting a networkand the QoS of the network are controlled by the policy server. A knownprotocol for policy servers is, e.g., a Common Open Policy Service(COPS) protocol specified in RFC 2478, a Recommendation for InternetProtocol, developed by the Internet Engineering Task Force (IETF) andpublished by the Internet Architecture Board (IAB).

The following method for priority control of packets in a particularflow on a network is known. For example, a relay node, called an edgenode, which is located on the boundary of the network, classifies thepackets flowing in the network into a plurality of classes of prioritycontrol; and, in the header of each packet flowing in, it sets one of“Diffserv Code Point (DSCP)” values that correspond to the classes ofpriority control for the packets. A relay node, called a core node,which is located at an inner point of the network, performs prioritycontrol and forwarding of the packets it has received, according to theDSCP value included in the header of every packet it received and incompliance with a predetermined rule. This technique is calledDifferentiated Services (Diffserv) and, e.g., as in Internet Protocol(IP) telephony, it is used to decrease a delay in transferring real-timepackets, such as voice packets, and video packets on the IP network,e.g., such as an IP telephony network.

The constitutions of a known session QoS control apparatus and a knownpolicy server are shown in FIG. 10. The session QoS control apparatuscomprises a session management database 150 and a session informationanalysis means 110. The policy server comprises a user communicationterminal and router management database 170 and a means forcommunication with a router 130.

As the network scale expands and VoIP users grow, in the method in whichQoS information for all sessions of the VoIP communication terminalsmust be set on the nodes beforehand, the loads on the nodes willincrease, resulting in an increase of the delay in relaying real-timepackets. Also, this method is unable to change a QoS information settingor the like in real time, responsive to a change in the states of VoIPusers. Because the SIP is a Layer 7 technique, there is also a problemin which the SIP server is incapable of direct control over the QoS ofthe network.

Furthermore, because the policy server cannot detect the start and endof a session communication between VoIP communication terminals, thepolicy server's operator must set a policy for each node in response tothe start and end of VoIP communication, a change of the user state, anda change of the session condition. However, with expansion of thenetwork, a frequent policy setting will be needed, and a situation wherethe operator's setting operation cannot keep up with the need willoccur.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a session QoScontrol apparatus which does not require the operator to perform policysetting, which can prevent a delay caused by superfluous policy settingin relaying packets at each node, and which can prevent an increase inthe loads on terminals.

In order to solve the above-described problems, in session communicationbetween users for which a QoS policy setting is enabled, QoS informationis added to a SIP user preference database in accordance with thepresent invention. Based on the SIP user preference database and SIPmessages, the QoS requirement per user is identified, and an appropriateQoS policy is set on the nodes to which caller and callee terminals areconnected, respectively.

More specifically, a session QoS control apparatus in accordance withthe present invention comprises a session management database in whichmanagement information for sessions between user communication terminalsis stored; a user communication terminal and router management databasein which mapping between a user communication terminal and a networknode to which the terminal is connected is stored; a user preferencedatabase in which user preference information representing a userrequirement associated with the identifier of a user communicationterminal is stored; a session information analysis means which analysesthe session state of a user terminal by referring to the sessionmanagement database and the user preference database; and a session QoScontrol means which determines a Quality of Service (QoS) policy for auser session, based on the result of session analysis performed by thesession information analysis means, which identifies a router on whichthe QoS policy should be set or canceled from the user communicationterminal and router management database, and which generates a sessionQoS command addressed to the router.

The session QoS command generated by the session QoS control means istransmitted to the destination router through the means forcommunication with a router and the session QoS policy setting orcancellation is performed on the router. Upon receiving user sessioninformation indicating a change of user state and/or a change of sessioncondition from a user communication terminal, the session informationanalysis means analyses the session state of the user terminal andupdates the user preference information in the user preference database,according to the result of the session analysis.

According to the present invention, in a VoIP communication for which aQoS policy setting is enabled, the following can be implemented: addingQoS information to the SIP user preference database, identifying the QoSrequirement for a SIP user session, and setting a QoS level per usersession. Also, by eliminating the need for manual policy setting by anoperator, the invention can prevent a delay caused by superfluous policysetting in relaying packets at each node, as well as prevent an increasein the loads on terminals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an apparatus using the session QoS controlmethod of the present invention;

FIG. 2 is a diagram which illustrates an example of network topology towhich the session QoS control method of the present invention isapplied;

FIG. 3 is a flowchart describing the operation by the session QoScontrol method of the present invention;

FIG. 4 is a sequence diagram illustrating the procedure for QoS settingfor a session between communication terminals by the session QoS controlapparatus of the present invention;

FIG. 5 is a sequence diagram illustrating the procedure for QoS settingby the session QoS control method of the present invention;

FIG. 6 is a diagram which illustrates an example of the structure of auser preference database 160 which is used by the session QoS controlapparatus of the present invention;

FIG. 7 is a diagram which illustrates an example of user sessioninformation described in SIP messages (INVITE message and OK message)which are exchanged between the session QoS control apparatuses of thepresent invention;

FIG. 8 is a diagram which illustrates an example of the structure of asession information management database which is used by the session QoScontrol apparatus of the present invention;

FIG. 9 is a diagram which illustrates an example of the structure of auser communication terminal and router management database which is usedby the session QoS control apparatus of the present invention; and

FIG. 10 is a diagram showing a known session QoS control apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be discussed hereinafter inan illustrative case where VoIP is used as the application, the SessionInitiation Protocol (SIP) is used as the user session control protocol,and a Common Line Interface (CLI) is used as the policy settingprotocol. However, the present invention is not limited to thecombination of the VoIP and the above-stated protocols.

FIG. 1 is a block diagram of a session QoS control apparatus 10 to whichthe session QoS control method of the present invention is applied.

The session QoS control apparatus 10 of the present invention iscomprised of a session management database 150 in which sessionmanagement information 201 for sessions between user communicationterminals is stored, a user preference database 160 in which userpreference information 202 representing the states of users and userrequirements is stored, a user communication terminal and routermanagement database 170 in which user communication terminal and routermanagement information representing what user communication terminalconnects to what node (router) is retained, a session informationanalysis means 110 which receives user session information 203 from auser communication terminal and analyses the session state of the userterminal by referring to the session management information 201 and theuser preference information 202 retrieved from the databases 150 and160, respectively, a session QoS control means 120 which determines aQuality of Service (QoS) policy for a user session, based on sessionanalysis result information 205 that is output from the sessioninformation analysis means 110, identifies a router on which the QoSpolicy should be set or canceled, based on the user communicationterminal and router management information 206, and generates a sessionQoS command addressed to the router, and a means for communication witha router 130 which transmits the session QoS command to the destinationrouter 30.

However, this embodiment may be modified such that the session QoScontrol means 120 passes the user session QoS policy 207 to the meansfor communication with a router 130, and the means for communicationwith a router 130 generates the session QoS command 208, based on theuser session QoS policy 207 and the user communication terminal androuter management information 206, and transmits this command.

Here, it is assumed in the initial state that the database 160 containspreset user preference information and that the database 170 containspreset user communication terminal and router management information.The user session information 203 indicates a change of user terminal(user) and/or a change of session communication condition detected by auser session state detection means 140 provided in a user communicationterminal.

As described above, the gist of the present invention is such that, in aVoIP communication that is performed on an IP network, the session QoScontrol apparatus 10 receives a SIP message transmitted from a usercommunication terminal (VoIP terminal) 20, the session QoS controlapparatus 10 generates a session QoS policy, based on the VoIP userpreference, and, by way of the CLI, the QoS policy information is set onthe node 30 to which the VoIP communication terminal is connected.

FIG. 2 shows an IP network in which Diffserv-based QoS control isperformed as an example of network topology to which the session QoScontrol method of the present invention is applied. More specifically,the diagram here is used to explain the network topology where a VoIPterminal 20 a with an IP address of “192.168.10.1” communicates with aVoIP terminal 20 b with an IP address of “192.168.20.1” via the IPnetwork 50 in which QoS can be controlled and the session QoS controloperation.

When initiating communication with the VoIP communication terminal 20 b,the VoIP communication terminal 20 a transmits a SIP message to asession QoS control apparatus 10 a of the present invention with an IPaddress of “192.168.100.10”. The SIP message transmitted by the VoIPcommunication terminal 20 a is transferred from the session QoS controlapparatus 10 a to a session QoS control apparatus 10 b with an IPaddress of “192.168.100.20”. Then, it is transferred from the sessionQoS control apparatus 10 b to the VoIP communication terminal 20 b.

During this message transfer, both the session QoS control apparatuses10 a and 10 b analyze the received SIP message and determine a sessionQoS policy, based on the user preference database 160. The session QoScontrol apparatus 10 a transmits the session QoS policy determined by itto an edge node 30 a with an IP address of “192.168.100.1” to which thecommunication terminal 20 a is connected, using the CLI. Also, thesession QoS control apparatus 10 b transmits the session QoS policydetermined by it to an edge node 30 b with an IP address of“192.168.100.2” to which the communication terminal 20 b is connected,using the CLI. In some implementation, the session QoS policy may betransmitted to core nodes in addition to the edge nodes. By thisnotification of the session QoS policy, the QoS policy is set on eachedge node so that VoIP packets are transferred preferentially and theVoIP service quality can be assured.

FIG. 3 is a flowchart describing the operation according to the sessionQoS control method of the present invention. Referring to the sessionQoS control apparatus 10 shown in FIG. 1, the session QoS control methodof the present invention will be explained below.

The communication terminal 20 checks for a change of session conditionand a change of user state by the user session state detection means140. In the case where, for example, the VoIP application runs, when theuser session state detection means 140 detects a change of voice qualityin the session or an IP address change as the user involved in thesession moves, it transmits an SIP message including user sessioninformation to the session QoS control apparatus 10.

When the session information analysis means 110 of the session QoScontrol apparatus 10 detects the change of session condition and/or thechange of user state (301) by the user session information, it searchesthe session management database by the above user session information(302) and judges the operating status of the session. The SIP messageincludes, e.g., the IP address and port number of the VoIP terminal, theIP address of the callee terminal, and the like as the user sessioninformation. From the SIP message, media information such as audio andvideo can be extracted and QoS setting according to the mediainformation can also be performed.

The session information analysis means 110 determines whether the end ofthe session has been detected (303). If the end of the session has beendetected, the session QoS control means 120 generates a cancel sessionQoS command to clear the QoS policy of the session. The command istransmitted through the means for communication with a router 130 to theappropriate node and the QoS setting is canceled (304). In the casewhere, for example, the Differserv technique is used, a policy to clearthe DSCP value for the session is generated and transmitted to the nodeand the QoS setting is cancelled. Thereafter, the session informationanalysis means 110 updates the session management database 150,according to the result of the session information analysis (307).

Otherwise, if the end of the session has not been detected in step 303,the session information analysis means 110 retrieves the QoS requirementof the user from the user preference database 160 and analyses thesession information (305). According to the result of this sessionanalysis, the session QoS control means 120 determines a session QoSpolicy and generates a set QoS command. This command is transmittedthrough the means for communication with a router 130 to the appropriatenode (306). In the case where, for example, the Differserv technique isused, after a DSCP value for the session is determined, the session QoSpolicy is generated and transmitted to the node and the QoS policy isset. The session information analysis means 110 updates the sessionmanagement database 150, according to the result of the sessioninformation analysis (307).

FIG. 4 is a sequence diagram which illustrates the procedure for QoSsetting for a session between communication terminals by the session QoScontrol apparatuses of the present invention. The diagram here shows thesequence in the case where the SIP is applied as the user sessioncontrol protocol and VoIP is used as the application.

One VoIP communication terminal A (20 a) transmits an INVITE message 401that is a request asking the callee to establish a two-party session toone session QoS control apparatus A (10 a). Having received the INVITEmessage, the session QoS control apparatus A (10 a) analyzes the sessioninformation described in the INVITE message, stores the sessioninformation into the session management database, and transfers theINVITE message 402 to the other session QoS control apparatus B (10 b).The session QoS control apparatus B (10 b), in turn, transfers theINVITE message 403 to the other VoIP communication terminal B (20 b).

Having received the INVITE message, the VoIP communication terminal Breturns an OK message (success indication) 404 to the session QoScontrol apparatus B (10 b) when it has become ready to establish thesession. Having received the OK message 404, the session QoS controlapparatus B (10 b) transfers the OK message 405 to the session QoScontrol apparatus A (10 a). The session QoS control apparatus A (10 a),in turn, transfers the OK message 406 to the VoIP communication terminalA. Having received the OK message, the VoIP communication terminal Aestablishes the two-party session and transmits an ACK message 407 thatindicates the start of VoIP communication to the session QoS controlapparatus A (10 a).

Having received the ACK message, the session QoS control apparatus A (10a) analyzes the user session information, based on the sessioninformation that has been stored on the session management database 150,and generates a session QoS command. Also, it retrieves the node A towhich the caller terminal A is connected from the terminal and routermanagement database 170 and transfers the session QoS command 409 to thenode A (408).

The node A (30 a) sets the QoS policy for the user session, based on thereceived session QoS command, and responds by returning a session QoSreport 410 indicating that the QoS setting has been completed to thesession QoS control apparatus A (10 a).

Upon having received the session QoS report, the session QoS controlapparatus A (10 a) transfers the ACK message 412 to the session QoScontrol apparatus B (10 b) (411). However, the session QoS controlapparatus A (10 a) may proceed to the next action immediately aftertransmitting the session QoS command without waiting for the receptionof the session QoS report from the node A.

Having received the ACK message, the session QoS control apparatus B (10b) transmits a session QoS command 414 to the node B to which the calleeterminal B is connected as the session QoS control apparatus A (10 a)does (413). The node B sets the QoS policy for the user session, basedon the session QoS command, and responds by returning a session QoSreport 415 indicating that the QoS setting has been completed to thesession QoS control apparatus B (10 b). Upon having received the sessionQoS report, the session QoS control apparatus B (10 b) transfers the ACKmessage 417 to the VoIP communication terminal B (20 b).

Through the foregoing operation, QoS policy setting on each edge node iscompleted. Thereafter, the node A (30 a) attaches QoS controlinformation (421) to a VoIP packet 420 that has been transmitted fromthe VoIP communication terminal A (20 a), and the node B (30 b) attachesQoS control information (423) to a VoIP packet 422 that has beentransmitted from the VoIP communication terminal (20 b). Thus, packetsfor which QoS is controlled are transferred on the network 50.

FIG. 5 is a sequence diagram illustrating the procedure for QoS settingby the session QoS control method of the present invention.

The user session state detection means 140 provided in the VoIPcommunication terminal transmits user session information denoting adetected state change to the session information analysis means 110 ofthe session QoS control apparatus 10 (501). Based on the received usersession information, the session information analysis means 110retrieves the current session management information from the sessionmanagement database 150 (502) and the registered user's requirementinformation from the user preference database 160 (503). Then, itanalyses the user session information in order to determine the sessionoperation (504). The user session information includes the voice qualitymeasured at the VoIP communication terminal, a change of the sessionstate as the user moves, and the like.

After analyzing the session information, the session informationanalysis means 110 updates the session management database 150 (505) andthe user preference database 160 (506), based on the analysis result.Then, it sends the session analysis result to the session QoS controlmeans 120 (507).

Having received the session analysis result, the session QoS controlmeans 120 retrieves what network node to which the user terminal isconnected from the user communication terminal and router managementdatabase 170 (508) and generates a session QoS command (509). Then, itupdates the user communication terminal and router management database170, if necessary, (510) and passes the session QoS command to the meansfor communication with a router (511), which then transmits the commandto the appropriate node (512).

FIG. 6 illustrates an example of the structure of the user preferencedatabase 160 which is used by the session QoS control apparatus of thepresent invention.

The user preference database stores information for controlling thesession QoS state according to user requirements. For example, for auser identified by SIP URL, its QoS requirement can be changed accordingto the user state and session condition. In this example, each row ofthe database is a record for one SIP Uniform Resource Locator (URL)associated with other items, such as location and IP address. When, forexample, the SIP URL of a user is “SIP:userA@192.168.100.10” and theuser location is office, its QoS requirement is set to the highest bevel“Gold.” Even for the same user, when the user location is home, its QoSrequirement is set to the lowest level “NA.”

FIG. 7 illustrates an example of user session information described inSIP messages (INVITE message and OK message) which are exchanged betweenthe session QoS control apparatuses of the present invention.

In the SIP, a session message is described in a Session DescriptionProtocol (SDP). In the description example shown in FIG. 7, a source IPaddress of “102.168.10.1”, a destination IP address of “192.160.20.1”, asource port number of “49170”, a transmission of “Audio” data media, anda Real time Transport Protocol (RTP) serving as the transmissionprotocol are specified.

FIG. 8 illustrates an example of the structure of the sessioninformation management database 150 which is used by the session QoScontrol apparatus of the present invention.

The session information management table stores information foridentifying each session. In this example, each row of the database is arecord for one session communication, consisting of Call-ID to uniquelyidentify a SIP-based session, To-tag, From-tag, the source IP addressand port number for session communication, the destination IP address,and the priority control level in relaying packets. Here, the DSCPvalues that are used in the Diffserv technique are employed to specifythe priority control level in relaying packets.

FIG. 9 illustrates an example of the structure of the user communicationterminal and router management database 170 which is used by the sessionQoS control apparatus of the present invention.

The user communication terminal and router management database storesinformation on what user communication terminal is connected to whatrouter, which is required for QoS policy setting. Particularly in thecase of the IP network, this table stores mapping between the IP addressof a user communication terminal and the IP address of a router. In thisexample, each row of the database is a record for one communicationterminal (VoIP communication terminal), consisting of the IP address ofthe communication terminal and the IP address of the node on which a QoSpolicy must be set for QoS priority control of packets transmitted fromthe communication terminal.

As described above, according to the present invention, in a VoIPcommunication for which the QoS policy setting is enabled, the followingcan be implemented: adding QoS information to the SIP user preferencedatabase, identifying the QoS requirement for a SIP user session, andsetting a QoS level per user session. Also, by eliminating the need formanual policy setting by the operator, the invention can prevent a delaycaused by superfluous policy setting in relaying packets at each node,as well as an increase in the loads on terminals.

1. A session QoS control apparatus which relays control information fora communication session between user communication terminals,comprising: a session management database in which managementinformation for sessions between user communication terminals is stored;a user communication terminal and router management database in whichmapping between a user communication terminal and a network node towhich the terminal is connected is stored; a user preference database inwhich-user preference information representing a user requirementassociated with the identifier of a user communication terminal isstored; a session information analysis means which analyses the sessionstate of a user terminal by referring to said session managementdatabase and said user preference database; and a session QoS controlmeans which determines a Quality of Service (QoS) policy for a usersession, based on the result of session analysis performed by saidsession information analysis means, identifies a router on which the QoSpolicy should be set from said user communication terminal and routermanagement database, and generates a session QoS command addressed tothe router; wherein for an occurrence of user session informationindicating a change of user state and/or a change of session conditionfrom a user communication terminal: said session information analysismeans analyses the session state of the user terminal in real-time byreferring to said session management database and said user preferencedatabase; and, said session QoS control means determines the QoS policyfor the user session in real-time, based on the result of sessionanalysis performed by said session information analysis means.